A salt core pressing die with notches and same-direction inclination and manufacturing process

Abstract

The present invention provides a salt core pressing mold with notches inclined in the same direction and a manufacturing process, comprising an upper mold and a lower mold, wherein a matching lower mold upper part is mounted on the lower mold, a salt core feeding area is reserved between the lower mold and the upper part of the lower mold, a spring connecting sleeve is arranged on the upper part of the lower mold, and a spring mold is arranged inside the spring connecting sleeve; a through hole for the spring connecting sleeve to be placed is arranged in the upper mold, and the process comprises mold assembly, salt material addition, salt material pressing and salt material drying. The salt core pressing mold with notches inclined in the same direction and the manufacturing process of the present invention can form the salt core with notches inclined in the same direction at one time, without the need for subsequent grinding process, thus saving time and ensuring the quality of the finished product; and due to the one-time integrated molding, the salt core has higher design strength and surface finish, and the finished salt core can better meet the quality requirements of the piston for internal cooling.

Description

Technical Field

[0001] The invention relates to a salt core pressing die for piston inner cooling and a manufacturing process thereof, and in particular to a salt core pressing die with notches inclined in the same direction and a manufacturing process thereof. Background Art

[0002] With the continuous improvement of national emission standards, the requirements for the performance of internal combustion engines are also increasing: high power, low fuel consumption, low noise, low emissions, etc. As an important core component of the internal combustion engine, the performance of the piston has become particularly important. In order to improve the performance of the piston under high-temperature reciprocating working conditions, the internal cooling channel structure design of the piston is becoming more and more complex, so as to reduce the temperature of the piston head during operation and improve the thermal fatigue performance of the piston.

[0003] At present, the salt core with notches on both sides in the same direction and the shape of the notches on both sides of the salt core cross section cannot be pressed and formed at one time. Therefore, the original production method of CNC machining the notches by CNC milling after turning or manually polishing the notches by comparing with samples after turning is generally adopted. These two production methods are costly and inefficient, and cannot be used in industrial production in large quantities. Summary of the invention

[0004] In order to make up for the deficiencies of the prior art, the present invention provides a salt core mold and a manufacturing process which have a simple structure, high reliability and a simpler manufacturing process.

[0005] The present invention is achieved through the following technical solutions:

[0006] A salt core pressing die with notches and inclined in the same direction comprises an upper die and a lower die, wherein a matching lower die upper part is mounted on the lower die, a salt core feeding area is reserved between the lower die and the lower die upper part, a spring connecting sleeve is arranged on the lower die upper part, a die spring is arranged in the spring connecting sleeve; a through hole is arranged in the upper die for the spring connecting sleeve to be placed.

[0007] The salt core pressing die with notches and inclined in the same direction described in the present invention has a groove on the upper part of the lower die, an internal thread is arranged inside the groove, and an external thread matching the internal thread of the groove is arranged at the bottom of the spring connecting sleeve.

[0008] The salt core pressing die with notches and inclined in the same direction described in the present invention comprises three groups of grooves and spring connecting sleeves.

[0009] In the salt core pressing die with notches and inclined in the same direction described in the present invention, the length of the die spring is greater than the length of the through hole.

[0010] A process for producing salt cores using a salt core pressing mold with a same-direction inclination and a notch, comprising the following steps:

[0011] Step 1: Assemble and fix the salt core mold.

[0012] ①Put the spring connection sleeve into the upper die;

[0013] ②Install the mold spring into the spring connecting sleeve in sequence;

[0014] ③ Connect the assembled upper die, die spring and spring connecting sleeve to the pressing cylinder;

[0015] ④Fix the lower die on the workbench, and place the upper part of the lower die on the lower die according to the position of the notch;

[0016] ⑤Operate the pressing cylinder downward until the spring connecting sleeve contacts the upper part of the lower die;

[0017] ⑥Fix the lower thread of the spring connecting sleeve with the upper groove thread of the lower die;

[0018] Step 2: Add salt.

[0019] ① The raw salt is screened using a filter screen;

[0020] ② The screened raw salt is mixed with auxiliary materials in a certain proportion;

[0021] Step 3: Salt core pressing,

[0022] ① Add the mixed salt into the salt core feeding area;

[0023] ② Operate the pressing cylinder to drive the upper die to press downward. During the pressing process, the die spring is compressed first, and the die spring transmits the elastic force to the upper part of the lower die through the spring connecting sleeve, so that the upper part of the lower die is always closely matched with the lower die during the entire pressing process;

[0024] ③ When the upper die 01 is pressed into place according to the set pressure value, the closed area formed by the upper die, the upper part of the lower die and the lower die is the salt core cross section, and the pressure is maintained to press out the salt core blank;

[0025] ④ After holding the pressure for a certain period of time, the upper die moves upward. During this process, the upper part of the lower die is always pressed against the lower die by the die spring. When the upper die moves upward to the point where the spring connecting sleeve contacts the countersunk hole, the spring connecting sleeve and the upper part of the lower die move upward together.

[0026] ⑤ When the upper die starts to move upward, the salt core blank loses the pressing force of the upper die. When the pressing stress is released, the salt core blank expands in the radial direction. At this time, the salt core blank is tightly attached to the upper part of the lower die under the action of the expansion force and moves upward together with the upper part of the lower die;

[0027] ⑥ After the upper part of the lower die moves up with the salt core blank, a discharge tray is placed on the lower die, and the pressing process of ①-② above is carried out again. At this time, the upper die pushes the salt core blank out of the upper part of the lower die onto the discharge tray;

[0028] Step 4: Drying the salt core,

[0029] The salt core blank is placed in a drying room with air humidity ≤25%RH for natural evaporation and drying for not less than 9.5 hours, and then the subsequent turning, drilling and sintering can be carried out.

[0030] The process for producing salt cores according to claim 5, characterized in that the pressure applied to the projected area of ​​the salt core blank in the vertical direction is 1200-1400 Kgf / cm 2 ; The effective stroke of the upper pressure cylinder is 350mm; The effective pressing stroke is ≥25mm.

[0031] In the process for producing salt cores of the present invention, the auxiliary materials in step 2 are water glass and talcum powder, and the mass proportions of the salt material, water glass and talcum powder are: 97%, 2.5% and 0.5%.

[0032] In the process for producing salt cores of the present invention, the sieve used for screening in step 2 has 20 meshes, and the mixing is performed by a mixer for 6-10 minutes.

[0033] In the process for producing salt cores of the present invention, the volume of the salt material added to the salt core feeding area in step three is 1.25 times the volume of the salt core blank.

[0034] The beneficial effects of the present invention are:

[0035] The pressing die and manufacturing process of the salt core with notches inclined in the same direction of the present invention can form the salt core with notches inclined in the same direction in one step, without the need for subsequent polishing steps, thus saving time and ensuring the quality of the finished product. Moreover, due to the one-step integrated molding, the salt core has higher design strength and surface finish, and the finished salt core can better meet the quality requirements of the piston for internal cooling. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be further described below in conjunction with the accompanying drawings.

[0037] Figure 1 It is a cross-sectional schematic diagram of the present invention;

[0038] Figure 2 It is a schematic diagram of the unloading cross section of the present invention;

[0039] Figure 3 This is a schematic diagram of the cross-sectional structure of the salt core with a notch and inclined in the same direction according to the present invention;

[0040] Figure 4 This is a schematic diagram of the structure of the salt core with a notch and an inclination in the same direction according to the present invention.

[0041] In the figure, 1 is the upper die; 2 is the die spring; 3 is the spring connecting sleeve; 4 is the upper part of the lower die; 5 is the lower die; 6 is the salt core feeding area; 7 is the unloading tray; 8 is the salt core blank. DETAILED DESCRIPTION

[0042] For ease of description, spatially relative terms such as "upper", "lower", "left", "right", etc. may be used herein to describe the relationship of one element or feature shown in the figure relative to another element or feature. It should be understood that, in addition to the orientation shown in the figure, the spatial terms are intended to include different orientations of the device in use or operation. For example, if the device in the figure is inverted, the elements described as being "below" other elements or features will be positioned "above" other elements or features. Therefore, the exemplary term "lower" can include both upper and lower orientations. The device can be positioned in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here can be interpreted accordingly.

[0043] Attached Figure 1-4 This is a specific embodiment of the present invention.

[0044] A salt core pressing die with notches and inclined in the same direction comprises an upper die 1 and a lower die 5. A matching lower die upper part 4 is mounted on the lower die 5, a salt core feeding area 6 is left between the lower die 5 and the lower die upper part 4, a spring connecting sleeve 3 is arranged on the lower die upper part 4, a die spring 2 is arranged in the spring connecting sleeve 3; a through hole is arranged in the upper die 1 for the spring connecting sleeve 3 to be placed.

[0045] The present invention provides a salt core pressing die with a same-direction inclination and a notch, wherein the upper portion 4 of the lower die is provided with a groove, the interior of the groove is provided with an internal thread, and the bottom of the spring connecting sleeve 3 is provided with an external thread matching the internal thread of the groove.

[0046] In the salt core pressing die with notches and inclined in the same direction of the present invention, the grooves and the spring connecting sleeves 3 are each in three groups.

[0047] In the salt core pressing die with notches and inclined in the same direction of the present invention, the length of the die spring 2 is greater than the length of the through hole.

[0048] A process for producing salt cores using a salt core pressing mold with a same-direction inclination and a notch, characterized in that it comprises the following steps:

[0049] Step 1: Assemble and fix the salt core mold.

[0050] ①Put the spring connection sleeve 3 into the upper die 1;

[0051] ②Insert the mold spring 2 into the spring connecting sleeve 3 in sequence;

[0052] ③ Connect the assembled upper die 1, die spring 2 and spring connecting sleeve 3 to the pressing cylinder;

[0053] ④ The lower die 5 is fixed on the workbench, and the upper part 4 of the lower die is placed on the lower die 5 according to the position of the notch;

[0054] ⑤ Operate the pressing cylinder downward until the spring connecting sleeve 3 contacts the upper part 4 of the lower die;

[0055] ⑥Fix the thread at the lower end of the spring connecting sleeve 3 with the thread at the groove 4 on the upper part of the lower die;

[0056] Step 2: Add salt.

[0057] ① The raw salt is screened using a filter sieve with a 20-mesh sieve;

[0058] ② The screened raw salt is mixed with auxiliary materials in a certain proportion, wherein the auxiliary materials are water glass and talcum powder, and the mass proportions of the salt, water glass and talcum powder are: 97%: 2.5% and 0.5%, and the mixture is mixed using a mixer for 6-10 minutes.

[0059] Step 3: Salt core pressing,

[0060] ① Add the mixed salt material to the salt core feeding area 6, wherein the volume of the salt material added to the salt core feeding area 6 is 1.25 times the volume of the salt core blank 8;

[0061] ② Operate the pressing cylinder to drive the upper die 1 to press downward. During the pressing process, the die spring 2 is compressed first. The die spring 2 transmits the elastic force to the upper part 4 of the lower die through the spring connecting sleeve 3, so that the upper part 4 of the lower die is always closely matched with the lower die 5 during the entire pressing process;

[0062] ③ When the upper die 01 is pressed into place according to the set pressure value, the closed area formed by the upper die 1, the upper part of the lower die 4 and the lower die 5 is the salt core cross section, and the pressure is maintained to press out the salt core blank 8;

[0063] ④ After holding the pressure for a certain period of time, the upper die 1 moves upward. During this process, the upper part 4 of the lower die is always pressed on the lower die 5 by the die spring 2. When the upper die 1 moves upward to the point where the spring connecting sleeve 3 contacts the countersunk hole, the spring connecting sleeve 3 and the upper part 4 of the lower die move upward together;

[0064] ⑤ When the upper die 1 starts to move upward, the salt core blank 8 loses the pressing force of the upper die 1. When the pressing stress is released, the salt core blank 8 causes the salt core to expand in the radial direction. At this time, the salt core blank is tightly attached to the upper part 4 of the lower die under the action of the expansion force and moves upward together with the upper part 4 of the lower die;

[0065] ⑥ After the upper part 4 of the lower die moves upward with the salt core blank 4, a discharge tray 7 is placed on the upper part of the lower die 5, and the pressing process of ①-② is performed again. At this time, the upper die 1 pushes the salt core blank 8 out of the upper part 4 of the lower die onto the discharge tray 7;

[0066] Step 4: Drying the salt core,

[0067] The salt core blank 8 is placed in a drying room with an air humidity of ≤25%RH for natural evaporation drying for not less than 9.5 hours, and then the subsequent turning, drilling and sintering can be carried out.

[0068] In the process for producing salt cores of the present invention, the pressure applied to the projected area of ​​the salt core blank in the vertical direction is 1200-1400 Kgf / cm2; the effective stroke of the upper pressure cylinder is 350 mm; and the effective pressing stroke is ≥25 mm.

[0069] The specific implementation of the present invention is described in detail above, but it is only used as an example. The present invention is not limited to the specific implementation cases described above, and equivalent modifications to the present invention are also within the protection scope of the present invention.

Claims

1. A process for producing a salt core with a notch and a same-direction inclination, comprising the following steps: Step 1: Assemble and fix the salt core mold. ① Place the spring connection sleeve (3) into the upper die (1); ②Insert the mold spring (2) into the spring connecting sleeve (3) in sequence; ③ Connect the assembled upper die (1), die spring (2) and spring connecting sleeve (3) to the pressing cylinder; ④ The lower die (5) is fixed on the workbench, and the upper part of the lower die (4) is placed on the lower die (5) according to the position of the notch; ⑤ Operate the pressing cylinder downward until the spring connecting sleeve (3) contacts the upper part (4) of the lower die; ⑥Fix the thread at the lower end of the spring connecting sleeve (3) and the thread at the groove on the upper part of the lower die (4); Step 2: Add salt. ① The raw salt is screened using a filter screen; ② The screened raw salt is mixed with auxiliary materials in a certain proportion; Step 3: Salt core pressing, ① Add the mixed salt into the salt core feeding area (6); ② The pressing cylinder is operated to drive the upper die (1) to press downward. During the pressing process, the die spring (2) is first compressed. The die spring (2) transmits the elastic force to the upper part (4) of the lower die through the spring connecting sleeve (3), so that the upper part (4) of the lower die is always closely matched with the lower die (5) during the entire pressing process; ③ When the upper die (1) is pressed into place according to the set pressure value, the closed area formed by the upper die (1), the upper part of the lower die (4) and the lower die (5) is the salt core cross section, and the pressure is maintained to press out the salt core blank (8); ④ After holding the pressure for a certain period of time, the upper die (1) moves upward. During this process, the upper part (4) of the lower die is pressed against the lower die (5) by the die spring (2). When the upper die (1) moves upward to the point where the spring connecting sleeve (3) contacts the countersunk hole, the spring connecting sleeve (3) and the upper part (4) of the lower die move upward together. ⑤ When the upper die (1) starts to move upward, the salt core blank (8) loses the pressing force of the upper die (1), and the salt core blank (8) expands in the radial direction when the pressing stress is released. At this time, the salt core blank is tightly attached to the upper part (4) of the lower die under the action of the expansion force, and moves upward together with the upper part (4) of the lower die; ⑥ After the upper part (4) of the lower die moves upward with the salt core blank (4) to the position, a discharge tray (7) is placed on the upper part of the lower die (5), and the pressing process of ①-② is repeated. At this time, the upper die (1) pushes the salt core blank (8) out of the upper part (4) of the lower die onto the discharge tray (7); Step 4: Drying the salt core, The salt core blank (8) is placed in a drying room with an air humidity of ≤25%RH and dried by natural evaporation for not less than 9.5 hours, and then the subsequent turning, drilling and sintering can be carried out; The mould comprises an upper mould (1) and a lower mould (5); a matching lower mould upper part (4) is mounted on the lower mould (5); a salt core feeding area (6) is left between the lower mould (5) and the lower mould upper part (4); a spring connecting sleeve (3) is arranged on the lower mould upper part (4); a mould spring (2) is arranged inside the spring connecting sleeve (3); a through hole is arranged in the upper mould (1) for the spring connecting sleeve (3) to be placed therein; a groove is arranged on the lower mould upper part (4); an internal thread is arranged inside the groove; and an external thread matching the internal thread of the groove is arranged at the bottom of the spring connecting sleeve (3).

2. The process for producing the same-direction inclined notched salt core according to claim 1, characterized in that: The grooves and spring connection sleeves (3) are each provided in three groups.

3. The process for producing the same-direction inclined notched salt core according to claim 1, characterized in that: The length of the mold spring (2) is greater than the length of the through hole.

4. The process for producing the same-direction inclined notched salt core according to claim 1, characterized in that: The pressure applied to the projected area of ​​the salt core blank in the vertical direction is 1200-1400Kgf / cm2; the effective stroke of the upper pressure cylinder is 350mm; the effective pressing stroke is ≥25mm.

5. The process for producing the same-direction inclined notched salt core according to claim 1, characterized in that: The auxiliary materials in step 2 are water glass and talcum powder, and the mass proportions of the salt, water glass and talcum powder are: 97%: 2.5% and 0.5%.

6. The process for producing the same-direction inclined notched salt core according to claim 1, characterized in that: The sieve used for sieving in step 2 has a 20-mesh hole, and the mixing is carried out using a mixer for 6-10 minutes.

7. The process for producing the same-direction inclined notched salt core according to claim 1, characterized in that: In step 3, the volume of the salt material added to the salt core feeding area (6) is 1.25 times the volume of the salt core blank (8).

Images